Apicobasal gradient of left ventricular myocardial edema underlies transient T-wave inversion and QT interval prolongation (Wellens' ECG pattern) in Tako-Tsubo cardiomyopathy

An Emerging Cardiovascular Disease: Takotsubo Syndrome

Takotsubo syndrome (TTS) is a recently identified cardiac disease, which is far from being completely known. The aims of this narrative review are to provide a better understanding of the pathophysiological features of TTS and to update clinical findings in order to improve the management of subjects affected by this syndrome (according to the most recent consensus papers issued by the international scientific societies). We based our search on the material obtained via PubMed up to April 2019. The terms used were "Takotsubo Syndrome and Takotsubo cardiomyopathy" in combination with "heart failure, pathophysiology, complications, diagnosis, and treatment." TTS is a reversible form of ventricular dysfunction usually characterized by akinesia of the apex in the absence of obstructive coronary artery disease. In its initial phase, TTS may be indistinguishable from AMI and is usually triggered by a sudden emotional/physical stressor which abruptly increases catecholamine levels. However, the mechanisms by which catecholamines or other unidentified molecules can cause myocardial dysfunction is unknown. In-hospital stay may be hampered by various life-threatening complications, while data on long-term survival remain scarce and unclear. Furthermore, TTS may sometimes recur. We believe that TTS is clearly a much more complex condition than previously thought. Much remains to be discovered about its pathophysiologic mechanisms, the role of the link between the heart and brain and that of triggering factors and gender, and the reasons why this syndrome displays different phenotypes and sometimes recurs. Undoubtedly, preliminary evidence from pathophysiological studies (mainly genetic studies) has shown promising advances. However, prospective randomized clinical trials are still needed in order to identify and to tailor the best medical treatments for TTS patients.

Takotsubo Cardiomyopathy-Acute Cardiac Dysfunction Associated With Neurological and Psychiatric Disorders

Takotsubo cardiomyopathy (TTC) is an acute and reversible cardiac wall motion abnormality of the left myocardium. Although many studies focused on etiology, diagnostic and treatment of TTC, precise clinical guidelines on TTC are not available. Research revealed emotional and physical triggering factors of TTC and emphasized the association of TTC with psychiatric and particularly acute neurological disorders. Similar clinical presentation of acute coronary syndrome (ACS) and TTC patients, makes an anamnestic screening for TTC risk factors necessary. In psychiatric anamnesis affective disorders and chronic anxiety disorders are presumably for TTC. Subarachnoid hemorrhages and status epilepticus are typical acute neurological associated with a higher risk for TTC. Moreover, magnetic resonance imaging (MRI) studies reveled brain alterations of the limbic system and reduced connectivity of central autonomic nervous system structures. Diagnosis of TTC is made by elevation of cardiac enzymes, electrocardiogram (ECG) and visualization of myocardial wall motion. Major differential diagnoses like acute coronary syndrome and myocarditis are hereby in synopsis with anamnesis with respect of possible emotional and physical triggering factors of TTC ruled out. In most cases the TTC typical wall motion abnormalities resolve in weeks and therapy is only necessary in hemodynamic instable patients and if rare complications, like cardiac wall ruptures occur. Recently, the two-parted International expert consensus document on Takotsubo syndrome was published, providing a detailed characterization of TTC and allows clinicians to understand this cardiac dysfunction with a multidisciplinary view.

Comparing the variants of takotsubo syndrome: an observational study of the ECG and structural changes from a New Zealand tertiary hospital

OBJECTIVES

In takotsubo syndrome, QTc prolongation is a measure of risk of potentially fatal arrhythmia. It is not known how this risk, or derangement of other markers, differs across the echo variants of takotsubo syndrome. Therefore, we sought to explore whether apical takotsubo syndrome differs from the variants of the syndrome in more ways than just regional wall motion pattern. As the region of affected myocardium is usually larger, we hypothesised that patients with the classic apical ballooning form of takotsubo syndrome would have more severe derangement of their markers.

DESIGN

Observational study of patients gathered from a prospective database (2010-2018) and by retrospective review (2006-2009).

SETTING

The sole tertiary hospital from a New Zealand region in which case clusters of takotsubo syndrome were precipitated by large earthquakes in 2010, 2011 and 2016.

PARTICIPANTS

A total of 222 patients who met a modified version of the Mayo criteria for takotsubo syndrome were included. All patients had digitally archived echocardiograms that were over-read by a second echocardiologist blinded to the clinical report.

PRIMARY OUTCOME MEASURES

Ejection fraction, peak troponin and QTc interval.

RESULTS

Patients with the apical form were older (p=0.011), had a lower initial left ventricular ejection fraction (35% vs 44%, p<0.0001) and a higher peak high-sensitivity troponin I (hsTnI) (p=0.01) than those with variant forms. There was no difference in the electrical abnormalities between the variants (QTc interval, heart rate, PR interval, QRS duration or T-wave axis). There was also no correlation between any of peak hsTnI, peak QTc and ejection fraction. QTc interval increased on day 2 and peaked on day 3 before falling steeply (p<0.0001).

CONCLUSIONS

The variants of takotsubo syndrome differ in more ways than just their echo pattern but do not differ in their electrical abnormalities. There is a dissociation between the structural and electrical abnormalities. QTc peaks on day 3 and then falls steeply.

Delayed ventricular pacing failure and correlations between pacing thresholds, left ventricular ejection fraction, and QTc values in a male with Takotsubo cardiomyopathy

BACKGROUND

Transient pacing failure caused by transient increased pacing threshold has been reported in patients with transient left ventricular apical dysfunction (Takotsubo cardiomyopathy [TC]). Normal pacing thresholds usually recover after normalization of systolic dysfunction.

HYPOTHESIS

Pacing failure correlates with clinics of TC.

METHODS

We report the case of a 76-year-old man with a dual chamber pacemaker, admitted for acute chest pain and dyspnea and final diagnosis of TC. One month after index admission, the patient came back complaining again of chest pain. Unexpectedly, admission electrocardiogram showed ventricular pacing failure and an increased pacing threshold. In the following weeks, pacing threshold gradually recovered with left ventricular ejection fraction and QTc values.

RESULTS

Ventricular pacing threshold correlated directly to QTc values and inversely to left ventricular ejection fraction over time (P < 0.05).

CONCLUSIONS

This is one of the first cases of delayed transient ventricular pacing failure in a male patient with transient left ventricular apical ballooning, in the presence of spared right ventricular function. Given the possibility of acute transient anomalies in myocardial impedance and pacing failure even in the subacute phase of TC several weeks after clinical onset of transient systolic dysfunction, pacing threshold should be carefully monitored in subjects with TC, both during the acute phase of the disease and in first months of follow-up after discharge. Ventricular pacing threshold correlated directly to QTc values and inversely to left ventricular ejection fraction over time.

Can you interpret the ECG under stress?

Stress (Takotsubo) cardiomyopathy (SC) is a cardiomyopathy characterised by transient myocardial dysfunction, commonly triggered by a surge in catecholamine. Electrocardiographic features may mimic other conditions, such as myocardial infarction. We presented two cases of SC and reviewed the electrocardiographic features of this disease entity.

Ventricular arrhythmias in patients with Takotsubo syndrome

Takotsubo syndrome (TTS) is a unique nonischemic cardiac disease characterized by acute myocardial dysfunction of the left and/or right ventricle. Patients are predominantly postmenopausal women and usually present with symptoms indistinguishable from acute coronary syndrome. Although the exact pathomechanisms of TTS remain elusive, increasing evidence suggests that sympathetic overdrive and catecholamine excess might play a central role. Despite the complete recovery of ventricular dysfunction within several days to weeks, patients with TTS exhibit considerable short- and long-term mortality rates and ventricular arrhythmias have been identified as key contributor to morbidity and mortality. This article summarizes the prevalence, underlying mechanisms, therapeutic strategies, and prognostic implications of ventricular arrhythmias in TTS. Furthermore, the need for implantable cardioverter-defibrillators is discussed in view of the transient character of the disease.

"Lambda-wave" ST-elevation is associated with severe prognosis in stress (takotsubo) cardiomyopathy

BACKGROUND

Persistent ST-segment elevation in acute coronary syndrome is associated with both short and long-term complications. By contrast, there is limited information about ST-elevation and its evolution during takotsubo (stress) cardiomyopathy (TTC).

AIM

To evaluate whether persistent downsloping ST-elevation in the early stages of TTC might correlate with short and long-term clinical events.

METHODS

One-hundred fifty-eight consecutive subjects with TTC were prospectively enrolled and assessed by electrocardiogram. Patients were classified in two groups according to the presence of downsloping ST-elevation ≥5 mm lasting at least 24 hr ("lambda-wave" ST-elevation group vs. without downsloping ST-elevation) in at least one/two contiguous leads.

RESULTS

Five (3.2%) patients, all female with a mean left ventricular ejection fraction 32 ± 5%, were included in the lambda-wave ST-elevation group. These patients were characterized by a higher prevalence of physical stressor (100% vs. 49%, p = 0.04) and higher admission and peak levels of troponin-I levels during hospitalization. Peak of ST-elevation in the lambda-wave ST-elevation group was reached 6 hr after admission and gradually decreased after 24 hr. In-hospital complications were observed in all the patients presenting lambda ST-elevation (100% vs. 23%, p = 0.03, OR: 29.1, p = 0.04); one patient presented endoventricular thrombosis and two died of cardiogenic shock. At long-term follow-up (mean 443 days), adverse events were observed in 80% of patients with lambda-wave ST-elevation (RR of adverse events at follow-up 32, p < 0.01).

CONCLUSION

Persistent downsloping lambda-wave ST-elevation during the acute phase of stress cardiomyopathy may be associated with a higher risk of adverse events at short and long-term follow-up.

International Expert Consensus Document on Takotsubo Syndrome (Part II): Diagnostic Workup, Outcome, and Management

The clinical expert consensus statement on takotsubo syndrome (TTS) part II focuses on the diagnostic workup, outcome, and management. The recommendations are based on interpretation of the limited clinical trial data currently available and experience of international TTS experts. It summarizes the diagnostic approach, which may facilitate correct and timely diagnosis. Furthermore, the document covers areas where controversies still exist in risk stratification and management of TTS. Based on available data the document provides recommendations on optimal care of such patients for practising physicians.

Ventricular arrhythmias and sudden cardiac arrest in Takotsubo cardiomyopathy: Incidence, predictive factors, and clinical implications

BACKGROUND

Takotsubo cardiomyopathy (TTC) is a stress-related transient cardiomyopathy. Life-threatening arrhythmias (LTA) can occur and worsen prognosis.

OBJECTIVE

The purpose of this study was to assess the incidence and outcome of LTA in TTC, as well as its predictive factors and clinical implications.

METHODS

We studied 214 consecutive cases of TTC over 8 years. The study cohort was divided into 2 groups: those with LTA (LTA group) and those without (non-LTA group). LTA was defined as ventricular tachycardia, ventricular fibrillation, or cardiac arrest.

RESULTS

LTA occurred in 23 (10.7%) of patients mainly in the first 24 hours of hospitalization: ventricular tachycardia (n = 2), ventricular fibrillation (n = 11), cardiac arrest (n = 10: 5 asystole, 3 complete heart block, and 2 sinoatrial block). LTAs were associated with lower left ventricular ejection fraction (LVEF) and a high rate of conduction disturbances. In-hospital (39.1% vs 8.9%; P < .001) and 1-year mortality (47.8% vs 14.1%; P < .001) rates were significantly increased in the LTA group. LVEF and QRS duration >105 ms were independent predictors of LTA. In cases where a device was implanted, conduction disturbances persisted after the index event despite complete recovery of LVEF. There was no ventricular arrhythmia recurrence during follow-up.

CONCLUSION

LTAs occur early in patients presenting with TTC and are associated with significantly worse short- and long-term prognosis. Left ventricular impairment and QRS duration >105 ms are independent predictors of LTA. Ventricular arrhythmias occurred in the acute phase without further recurrence recorded in hospital survivors, whereas severe conduction disorders persisted during long-term follow-up. These findings may have implications on the choice of device therapy for this specific patient subgroup.

Association of prolonged QTc interval with Takotsubo cardiomyopathy: A neurocardiac syndrome inside the mystery of the insula of Reil

The Takotsubo cardiomyopathy is often considered autochthonous to the heart, although the primary problem may be not in the heart muscle itself. Instead, similar to several Takotsubo-like cardiac pathologies seen in acute neurological diseases, it may reflect the capacity of the nervous system to injure the heart. Persuasive evidence exists that shocking emotional stress promotes direct heart injuries. Moreover, clinical and laboratory research shows that cardiac structural damage can occur in the presence of a normal heart, especially in the context of seizures, stroke, and traumatic brain injury or under conditions of psychological stress. The aim of this review is to summarize the clinical implications of these observations, several of which focus on the pivotal role of the insula of Reil in the brain-heart connection, to unravel the mystery of Takotsubo cardiomyopathy pathogenesis.

T-Wave Abnormality as Electrocardiographic Signature of Myocardial Edema in Non-ST-Elevation Acute Coronary Syndromes

Background

T‐wave abnormalities are common during the acute phase of non‐ST‐segment elevation acute coronary syndromes, but mechanisms underlying their occurrence are unclear. We hypothesized that T‐wave abnormalities in the presentation of non‐ST‐segment elevation acute coronary syndromes correspond to the presence of myocardial edema.

Methods and Results

Secondary analysis of a previously enrolled prospective cohort of patients presenting with non‐ST‐segment elevation acute coronary syndromes was conducted. Twelve‐lead electrocardiography (ECG) and cardiac magnetic resonance with T2‐weighted imaging were acquired before invasive coronary angiography. ECGs were classified dichotomously (ie, ischemic versus normal/nonischemic) and nominally according to patterns of presentation: no ST‐ or T‐wave abnormalities, isolated T‐wave abnormality, isolated ST depression, ST depression+T‐wave abnormality. Myocardial edema was determined by expert review of T2‐weighted images. Of 86 subjects (65% male, 59.4 years), 36 showed normal/nonischemic ECG, 25 isolated T‐wave abnormalities, 11 isolated ST depression, and 14 ST depression+T‐wave abnormality. Of 30 edema‐negative subjects, 24 (80%) had normal/nonischemic ECGs. Isolated T‐wave abnormality was significantly more prevalent in edema‐positive versus edema‐negative subjects (41.1% versus 6.7%, P=0.001). By multivariate analysis, an ischemic ECG showed a strong association with myocardial edema (odds ratio 12.23, 95% confidence interval 3.65‐40.94, P<0.0001). Among individual ECG profiles, isolated T‐wave abnormality was the single strongest predictor of myocardial edema (odds ratio 23.84, 95% confidence interval 4.30‐132, P<0.0001). Isolated T‐wave abnormality was highly specific (93%) but insensitive (43%) for detecting myocardial edema.

Conclusions

T‐wave abnormalities in the setting of non‐ST‐segment elevation acute coronary syndromes are related to the presence of myocardial edema. High specificity of this ECG alteration identifies a change in ischemic myocardium associated with worse outcomes that is potentially reversible.

Frequency of Inverted Electrocardiographic T Waves (Cerebral T Waves) in Patients With Acute Strokes and Their Relation to Left Ventricular Wall Motion Abnormalities

Transient, symmetric, and deep inverted electrocardiogram (ECG) T waves in the setting of stroke, commonly referred to as cerebral T waves, are rare, and the underlying mechanism is unclear. Our study aimed to test the hypothesis that cerebral T waves are associated with transient cardiac dysfunction. This retrospective study included 800 patients admitted with the primary diagnosis of hemorrhagic or ischemic stroke. ECGs were examined for cerebral T waves, defined as T-wave inversion of ≥5 mm depth in ≥4 contiguous precordial leads. Echocardiograms of those meeting these criteria were examined for the presence of left ventricular (LV) wall motion abnormalities. Follow-up evaluation included both ECG and echocardiogram. Of the 800 patients, 17 had cerebral T waves on ECG (2.1%). All 17 patients had ischemic strokes, of which 11 were in the middle cerebral artery distribution (65%), and 2 were cerebellar (12%), whereas the remaining 4 involved other locations. Follow-up ECG showed resolution of the T-wave changes in all 17 patients. Of these patients, 14 (82%) had normal wall motion, and 3 had transient wall motion abnormalities (18%). Two of these patients had Takotsubo-like cardiomyopathy with apical ballooning, and the third had globally reduced LV function. Coronary angiography showed no significant disease to explain the LV dysfunction. In summary, in our cohort of patients with acute stroke, cerebral T waves were rare and occurred only in ischemic stroke. Eighteen percent of patients with cerebral T waves had significant transient wall motion abnormalities. Patients with stroke with cerebral T waves, especially in those with ischemic strokes, should be assessed for cardiac dysfunction.

Fast ‘wandering’ Takotsubo syndrome: atypical mixed evolution from apical to mid-ventricular ballooning

We report the case of a 53-year-old woman admitted for typical chest pain and a diagnosis of Takotsubo syndrome (TTS). Initial echocardiographic presentation was characterized by apical and mid-ventricular akinesis and basal hyper-kinesis. Unexpectedly, later after admission, echocardiography showed recovered apical akinesis with an apparent ‘migration’ of systolic dysfunction to mid-ventricular segment and hyper-kinesis of apical and basal segments. One week after admission, left ventricular contractility completely recovered and cardiac magnetic resonance imaging did not show signs of subendocardial late-enhancement and myocardial edema. Cases of TTS may therefore occasionally rapidly ‘wander’ within left ventricular segments, raising doubts over the so far used classification of left ventricular patterns of ballooning in subjects with TTS (typical/atypical). Apparently, different patterns can rapidly evolve into each other. The absence of late-enhancement at cardiac magnetic resonance imaging could hypothetically identify rapidly ‘wandering’ cases.

Dynamic changes of QTc interval and prognostic significance in takotsubo (stress) cardiomyopathy

BACKGROUND

Prolonged QT corrected (QTc) intervals are associated with adverse cardiovascular outcomes both in healthy and high-risk populations. Our objective was to evaluate the QTc intervals during a takotsubo cardiomyopathy (TTC) episodes and their potential prognostic role.

HYPOTHESIS

Dynamic changes of QTc interval during hospitalization for TTC could be associated with outcome at follow-up.

METHODS

Fifty-two consecutive patients hospitalized for TTC were enrolled. Twelve-lead electrocardiogram (ECG) was performed within 3 h after admission and repeated after 3, 5, and 7 days. Patients were classified in 2 groups: group 1 presented the maximal QTc interval length at admission and group 2 developed maximal QTc interval length after admission.

RESULTS

Mean admission QTc interval was 493 ± 71 ms and mean QTc peak interval was 550 ± 76 ms (P < 0.001). Seventeen (33%) patients were included in group 1 and 35 (67%) patients in group 2. There were no differences for cardiovascular risk factors and in terms of ECG findings such as ST elevation, ST depression, and inverted T waves. Rates of adverse events during hospitalization among patients of group 1 and 2 were different although not significantly (20% vs 6%, P = 0.22). After 647 days follow-up, patients of group 1 presented higher risk of cardiovascular rehospitalization (31% vs 6%, P = 0.013; log-rank, P < 0.01). At multivariate analysis, including age and gender, a prolonged QTc interval at admission was significantly associated with higher risk of rehospitalization at follow-up (hazard ratio: 1.07 every 10 ms, 95% confidence interval: 1.003-1.14, P = 0.04).

CONCLUSIONS

Prolonged QTc intervals at admission during a TTC episode could be associated with a higher risk of cardiovascular rehospitalization at follow-up. Dynamic increase of QTc intervals after admission are characterized by a trend toward a better prognosis.

Takotsubo syndrome presenting as syncope in a patient with permanent pacemaker

Takotsubo syndrome is an acute reversible heart failure syndrome triggered by physical or emotional stress, especially in postmenopausal women. Herein, we describe a case of a 31-year-old pacemaker dependent lady who presented with syncope after she was bereaved of her father. Electrocardiogram at admission revealed ventricular paced rhythm at 60/min, prolonged QT interval and frequent runs of torsades de pointes. Transthoracic echocardiogram and left ventriculogram revealed findings typical of Takotsubo syndrome. QT prolongation and torsade de pointes in the context of fixed-rate ventricular pacing imply direct catecholamine toxicity on the ventricular myocardium independent of heart rate.

The ECG in the differential diagnosis between takotsubo cardiomyopathy and acute coronary syndrome

INTRODUCTION

Takotsubo cardiomyopathy (TC) is an acquired cardiomyopathy affecting mostly postmenopausal women mimicking an acute coronary syndrome (ACS). TC clinical presentation involves chest pain, elevated cardiac enzymes, wall motion abnormalities and electrocardiographic changes, all of which share striking similarities to ACS. Areas covered: Differential diagnosis between TC and ACS can be complex since there are no reliable and widely-accepted electrocardiographic criteria and, at the moment, only coronary angiography can rule out one of the two diagnoses with good certainty. The present review will discuss the pros and cons of the ECG in TC, focusing on how the signal changes through the acute phase, the hospitalization, and after discharge. Specific information will be provided for each component of the ECG trace, and potential pitfalls will be highlighted, in order get to the core of this important unmet clinical issue. Expert commentary: There are at least several reasons why the ECG is still not considered a useful tool in differential diagnosis between TC and ACS. These include recent awareness of the syndrome, lack of evidence-based therapy, and, more importantly, a wide range of ECG features according to race, patient characteristics, wall motion abnormalities, triggers, and time from symptoms onset.

Prognostic Usefulness of the Ballooning Pattern in Patients With Takotsubo Cardiomyopathy

The aim of the present analysis was to evaluate the prognostic impact of different ballooning patterns in patients with Takotsubo cardiomyopathy (TTC). A total of 285 consecutive patients with TTC were included. Clinical characteristics and short- and long-term outcomes were compared between patients with typical apical ballooning (n = 204) and patients with an atypical ballooning pattern including midventricular and basal ballooning (n = 81). Patients with typical apical ballooning were significantly older (73.3 ± 10.2 vs 68.4 ± 10.3 years; p <0.01) and had a higher prevalence of diabetes mellitus (25.5% vs 12.3%; p = 0.02). The initial left ventricular (LV) ejection fraction was significantly lower in case of apical ballooning (41.5 ± 10.4% vs 46.9 ± 10.9%; p <0.01) but recovered to normal values in both groups (58.4 ± 8.0 vs 59.7 ± 7.0; p = 0.25). Although 28-day mortality did not differ significantly (p = 0.10), typical apical ballooning was associated with an increased 6-month (13.4% vs 1.3%; hazard ratio [HR] 10.81, 95% confidence interval [CI] 1.47 to 79.66; p = 0.02) and long-term mortality rates (28.9% vs 14.5%; HR 2.24, 95% CI 1.17 to 4.71; p = 0.02). A landmark analysis which included only patients who survived the first 6 months after the initial event demonstrated similar mortality rates in patients with typical (17.9%) and atypical (13.3%) ballooning (HR 1.36, 95% CI 0.67 to 2.79; p = 0.40). In conclusion, in patients with TTC, typical apical ballooning is associated with more severe LV dysfunction at acute presentation and higher mortality rates within the first 6 months after the initial event. After complete recovery of LV function, prognosis is similar in patients with typical and atypical ballooning patterns.

Comparison of Electric- and Magnetic-Cardiograms Produced by Myocardial Ischemia in Models of the Human Ventricle and Torso

Myocardial ventricular ischemia arises from a lack of blood supply to the heart, which may cause abnormal repolarization and excitation wave conduction patterns in the tissue, leading to cardiac arrhythmias and even sudden death. Current diagnosis of cardiac ischemia by the 12-lead electrocardiogram (ECG) has limitations as they are insensitive in many cases and may show unnoticeable differences to normal patterns. As the magnetic field provides extra information on cardiac excitation and is more sensitive to tangential currents to the surface of the chest, whereas the electric field is more sensitive to flux currents, it has been hypothesized that the magnetocardiogram (MCG) may provide a complementary method to the ECG in ischemic diagnosis. However, it is unclear yet about the differences in sensitivity regions of body surface ECG and MCG signals to ischemic conditions. The aim of this study was to investigate such differences by using 12-, 36- ECG and 36-MCG computed from multi-scale biophysically detailed computational models of the human ventricles and torso in both control and ischemic conditions. It was shown that ischemia produced changes in the ECG and MCG signals in the QRS complex, T-wave and ST-segment, with greater relative differences seen in the 36-lead ECG and MCG as compared to the 12-leads ECG (34% and 37% vs 26%, respectively). The 36-lead ECG showed more averaged sensitivity than the MCG in the change of T-wave due to ischemia (37% vs 32%, respectively), whereas the MCG showed greater sensitivity than the ECG in the change of the ST-segment (50% vs 40%, respectively). In addition, both MCG and ECG showed regional-dependent changes to ischemia, but with MCG showing a stronger correlation between ischemic region in the heart. In conclusion, MCG shows more sensitivity than ECG in response to ischemia, which may provide an alternative method for the diagnosis of ischemia.

Management of arrhythmias in patients with Takotsubo cardiomyopathy: Is the implantation of permanent devices necessary?

BACKGROUND

Arrhythmias are frequent in Takotsubo cardiomyopathy (TTC) and a major determinant of outcome.

OBJECTIVE

The purpose of this study was to provide a rationale for management strategies, particularly for permanent device implantation given the reversible nature of TTC.

METHODS

Treatment strategies of arrhythmias including ventricular fibrillation (VF), ventricular tachycardia (VT), asystole, pulseless electrical activity, and complete atrioventricular (AV) or sinoatrial block were assessed in a bicentric cohort of consecutive patients with TTC (n = 286) with a mean follow-up period of 3.3 ± 2.4 years.

RESULTS

The prevalence of arrhythmias during the acute phase of TTC was 12.2% (n = 35), consisting predominantly of VT (n = 16 [5.6%]), VF (n = 7 [2.4%]), and complete AV block (n = 8 [2.8%]). Seven patients received a permanent pacemaker because of complete AV (n = 6) or sinoatrial (n = 1) block. Regular device checkups were available in 2 patients and demonstrated ongoing high-degree AV block despite recovery of left ventricular function. Three patients with transient bradyarrhythmias who did not receive devices died shortly after hospital discharge from unknown causes. One patient received an implantable cardioverter-defibrillator after resuscitation for VF and did not require device interventions during 2-year follow-up. Patients with polymorphic VT (n = 7), monomorphic VT (n = 6), or VF (n = 2) who were discharged from hospital survived or died of noncardiac reasons, with the cause of death remaining unclear in 1 patient with monomorphic sustained VT.

CONCLUSION

Our data suggest that bradyarrhythmias in the acute setting of TTC may require permanent pacemaker implantation. In contrast, polymorphic ventricular arrhythmias might be managed with a temporary approach (eg, wearable cardioverter-defibrillators) until recovery of repolarization time and left ventricular function.

TakoTsubo cardiomyopathy: unravelling the malignant consequences of a benign disease with cardiac magnetic resonance

TakoTsubo cardiomyopathy (TCM) is a unique type of reversible cardiomyopathy that is precipitated by a stressful emotional or physical event. The increasing incidence is due to the greater use of emergency coronary angiography, newer cardiac biomarkers together with more sensitive cardiac imaging techniques. Few case reports have documented how TCM can present with malignant arrhythmias such as torsades de pointes caused by the repolarisation abnormalities or QTc prolongation. Although TCM is usually considered a benign reversible condition, its associated arrhythmic risk is increasingly recognised. TCM often presents as an acute coronary syndrome with unobstructed coronary arteries at angiography. In this patient population, cardiac magnetic resonance (CMR) is a useful tool to establish a differential diagnosis, discriminating TCM from acute myocarditis and myocardial infarction with spontaneous recanalisation. CMR is becoming a promising new diagnostic modality in risk stratifying patients with potential higher arrhythmic risk.

Relationship between T-wave inversion and transmural myocardial edema as evidenced by cardiac magnetic resonance in patients with clinically suspected acute myocarditis: clinical and prognostic implications

BACKGROUND

The pathophysiologic mechanisms and the prognostic meaning of electrocardiographic (ECG) T-wave inversion (TWI) occurring in a subgroup of patients with clinically suspected acute myocarditis remain to be elucidated. Contrast-enhanced cardiac magnetic resonance (CMR) offers the potential to identify myocardial tissue changes such as edema and/or fibrosis which may underlie TWI.

METHODS AND RESULTS

We studied 76 consecutive patients (median age 34years) with clinically suspected acute myocarditis, using a comprehensive CMR protocol which included T2 weighted sequences for myocardial edema. At the time of CMR, TWI was observed in 21 (27%) patients. There was a statistically significant association of TWI with the median number of left ventricular (LV) segments showing both any pattern of myocardial edema (transmural and non-transmural) [5 (3-7) vs. 3 (2-4); p=0.015] and myocardial late-gadolinium-enhancement [4 (3-7) vs. 3 (2-4); p=0.002]. Transmural myocardial edema involving ≥2 LV segments was found in 17/21 (81%) patients with TWI versus 13/55 (24%) patients without TWI (p<0.001) and remained the only independent predictor of TWI at multivariable analysis (OR=9.96; 95%CI=2.71-36.6; p=0.001). Overall, topographic concordance between the location of TWI across the ECG leads and the regional distribution of transmural myocardial edema was 88%. There was no association between acute TWI and reduced LV ejection fraction (<55%) at 6-months of follow-up.

CONCLUSIONS

This is the first study to demonstrate an association between LV transmural myocardial edema as evidenced by CMR sequences and TWI in clinically suspected acute myocarditis. As an expression of reversible myocardial edema, development of TWI during the acute disease phase was not a predictor of LV systolic dysfunction at follow-up.

The Role of Transmural Repolarization Gradient in the Inversion of Cardiac Electric Field: Model Study of ECG in Hypothermia

BACKGROUND

The changes in ventricular repolarization gradients lead to significant alterations of the electrocardiographic body surface T waves up to the T wave inversion. However, the contribution of a specific gradient remains to be elucidated. The objective of the present investigation was to study the role of the transmural repolarization gradient in the inversion of the body surface T wave with a mathematical model of the hypothermia-induced changes of ventricular repolarization.

METHODS

By means of mathematical simulation, we set the hypothermic action potential duration (APD) distribution on the rabbit ventricular epicardium as it was previously experimentally documented. Then the parameters of the body surface potential distribution were tested with the introduction of different scenarios of the endocardial and epicardial APD behavior in hypothermia resulting in the unchanged, reversed or enlarged transmural repolarization gradient.

RESULTS

The reversal of epicardial repolarization gradients (apicobasal, anterior-posterior and interventricular) caused the inversion of the T waves regardless of the direction of the transmural repolarization gradient. However, the most realistic body surface potentials were obtained when the endocardial APDs were not changed under hypothermia while the epicardial APDs prolonged. This produced the reversed and increased transmural repolarization gradient in absolute magnitude. The body surface potentials simulated under the unchanged transmural gradient were reduced in comparison to those simulated under the reversed transmural gradient.

CONCLUSIONS

The simulations demonstrated that the transmural repolarization gradient did not play a crucial role in the cardiac electric field inversion under hypothermia, but its magnitude and direction contribute to the T wave amplitude.

Distinctive Electrocardiographic Features in African Americans Diagnosed with Takotsubo Cardiomyopathy

BACKGROUND

Takotsubo cardiomyopathy (TC) can resemble acute anterior ST-elevation myocardial infarction. Most studies have examined TC in Asians and Caucasians (non-African Americans [AA]), while very few cases have been reported in AA. We aimed to assess the electrocardiographic features of TC in AA patients and compare them to non-AA TC patients.

METHODS

We retrospectively compared electrocardiograms of 52 AA and 47 non-AA patients diagnosed with TC. All patients met the modified Mayo Clinic criteria for the diagnosis of TC. Information collected included PR interval, QRS duration and amplitude, QT interval in milliseconds (msec) adjusted for heart rate (QTc), ST-segment deviation at the J point in limb and precordial leads (≥1 mm), ST elevation (≥1 mm), and T-wave inversion (≥0.5 mm).

RESULTS

T-wave inversion was more prevalent on presentation among AA patients (82% vs 48% in non-AA; P < 0.01), whereas ST depression was more common among non-AA (21% vs 7% in AA; P = 0.05). T-wave inversions in AA patients were frequent in both limb and precordial leads, whereas T-wave inversions in non-AA were limited to precordial leads. The average QTc upon presentation in AA was longer than non-AA (491 msec in AA vs 456 msec in non-AA; P < 0.01) as was the maximum average QTc during index hospitalization (527 msec in AA vs 497 msec in non-AA, P = 0.03).

CONCLUSION

In patients presenting with TC, AA patients more frequently present with diffuse T-wave inversions and a more prolonged QTc, whereas non-AA patients more often present with ST depressions. AA patients also more frequently present with T-wave inversions diffusely, whereas non-AA patients present with T-wave inversions more limited to the precordial leads.

Prominent J-wave and T-wave alternans associated with mechanical alternans in a patient with takotsubo cardiomyopathy

A 74-year-old woman with takotsubo cardiomyopathy developed polymorphic ventricular tachycardia during the acute phase. She exhibited prominent J-wave and T-wave alternans preceding ventricular tachycardia. These abnormalities disappeared after recovery from myocardial stunning.

[ECG in patients with tako tsubo cardiomyopathy]

Takotsubo cardiomyopathy, also known as transient left ventricular ballooning and stress myocardiopathy, has been diagnosed increasingly more over the last decade. The takotsubo syndrome mimics acute myocardial infarction in symptoms and in electrocardiographic findings. There are two major types of takotsubo cardiomyopathy: the classical type with left ventricular apical ballooning and a type with midventricular ballooning. Both types show different electrocardiographic patterns at presentation. The present article describes classical electrocardiographic findings of the acute and subacute phases of takotsubo cardiomyopathy.

The Role of Cardiac MRI in Patients with Troponin-Positive Chest Pain and Unobstructed Coronary Arteries

Acute coronary syndrome (ACS) still remains one of the leading causes of mortality and morbidity worldwide. Seven to fifteen percent of patients presenting with ACS have unobstructed coronary artery disease (CAD) on urgent angiography. Patients with ACS and unobstructed coronary arteries represent a clinical dilemma and their diagnosis and management is quite variable in current practice. Cardiovascular magnetic resonance imaging with its unique non-invasive myocardial tissue characterization property has the potential to identify underlying etiologies and reach a final diagnosis. These include acute and chronic myocarditis, embolic/spontaneous recanalization myocardial infarction, and Tako-Tsubo cardiomyopathy, and other conditions. Establishing a final diagnosis has a direct implication on patient's management and prognosis. In this article, we have reviewed the current evidence on the diagnostic role of cardiac magnetic resonance (CMR) in patients with ACS and unobstructed coronary arteries. We have also highlighted the potential role of CMR as a risk stratification or prognostication tool for this patient population.

Negative T wave in ischemic heart disease: a consensus article

BACKGROUND

For many years was considered that negative T wave in ischemic heart disease represents ischemia and for many authors located in subepicardial area.

METHODS

We performed a review based in the literature and in the experience of the authors commenting the real significance of the presence of negative T wave in patients with ischemic heart disease.

RESULTS

The negative T wave may be of primary or secondary type. Negative T wave observed in ischemic heart disease are of primary origin, therefore not a consequence of abnormal repolarization pattern. The negative T wave of ischemic origin presents the following characteristics: (1) are symmetrical and of variable deepness; (2) present mirror patterns; (3) starts in the second part of repolarization; and (4) may be accompanied by positive or negative U wave. The negative T wave of ischemic origin may be seen in the following clinical settings: (1) postmyocardial infarction due to a window effect of necrotic zone and (2) as a consequence of reperfusion in case of aborted MI when the artery has opened spontaneously, or after fibrinolysis, PCI, or coronary spasm.

CONCLUSION

Acute ongoing ischemia do not cause negative T wave. This pattern appears when the ongoing ischemia is vanishing or in the chronic phase. In all these cases the cause of negative T wave is not located in the subepicardial area. Furthermore, positive exercise testing is expressed by ST depression never by isolated negative T wave. There are many circumstances that may present negative T wave outside ischemic heart disease and that have been discussed in this paper.